TY - CHAP A1 - Seelig, Torsten A1 - Harlander, Uwe A1 - Borcia, Ion-Dan A1 - Scurtu, Nicoleta A1 - Egbers, Christoph A1 - Klein, Marten A1 - Ghasemi, Abouzar A1 - Will, Andreas A1 - Schaller, Eberhard T1 - Inertial waves in rotating cylindrical annulus: theory, experiment and simulations T2 - Book of abstracts, 9th European Fluid Mechanics Conference (EFMC), 9-13 September, Rome, Italy Y1 - 2012 UR - http://www.efmc9.eu/absbook/index.html ER - TY - CHAP A1 - Kerstein, Alan R. A1 - Glawe, Christoph A1 - Schmidt, Heiko A1 - Klein, Rupert A1 - Gonzalez-Juez, Esteban D. A1 - Schmidt, Rodney T1 - Computational modeling of scalar transport and buoyancy effects in turbulent flows using ODTLES T2 - Bulletin of the American Physical Society Y1 - 2012 UR - http://meeting.aps.org/Meeting/DFD12/Event/176984 N1 - 65th Annual Meeting of the APS Division of Fluid Dynamics, Sunday–Tuesday, November 18–20, 2012 San Diego, California VL - 57 IS - 17 ER - TY - CHAP A1 - Glawe, Christoph A1 - Klein, Rupert A1 - Kerstein, Alan R. A1 - Schmidt, Heiko T1 - Towards the simulation of gravity waves using the One-Dimensional Turbulence model T2 - EGU General Assembly 2012, held 22-27 April, 2012 in Vienna Y1 - 2012 UR - http://meetingorganizer.copernicus.org/EGU2012/EGU2012-4821.pdf N1 - EGU2012-4821 ER - TY - CHAP A1 - Seelig, Torsten A1 - Borcia, Ion-Dan A1 - Klein, Marten A1 - Ghasemi, Abouzar A1 - Will, Andreas A1 - Egbers, Christoph A1 - Schaller, Eberhard A1 - Harlander, Uwe T1 - Inertial waves and wave attractors in a rotating annulus with inner or outer cylinder libration T2 - European Geosciences Union (EGU), 10th General Assembly, Vienna, Austria, 07 – 12 April 2013 Y1 - 2013 UR - http://meetingorganizer.copernicus.org/EGU2013/EGU2013-7602.pdf N1 - EGU2013-7602 ER - TY - GEN A1 - Gerlich, Lukas A1 - Ohsiek, Susanne A1 - Klein, Christoph A1 - Geiß, Mario A1 - Friedemann, Michael A1 - Kücher, Peter A1 - Schmeißer, Dieter T1 - Interface engineering for the TaN/Ta barrier film deposition process to control Ta-crystal growth T2 - Microelectronic Engineering N2 - As a consequence of device shrinking the resistivity of the widely used TaN/Ta double barrier layer becomes an increasingly important parameter for device speed beyond the 32 nm technology node. In this study we describe the optimization of the deposition of TaN/Ta stacks in such a way that tantalum nitride layer thickness is minimized and tantalum grows in the favorable conducting alpha-phase. In the first part of the study we usedin situ ARXPS to investigate the growth of different tantalum nitride layers on SiO2 and SiOCH as a function of deposition time, nitrogen flow and deposition power. In the second part we analyzed the crystalline phase of a 20 nm thick tantalum layer deposited on top of the same series of tantalum nitride layers characterized in the growth study. The main findings are the appearance of tan-talum carbide and tantalum silicide as interface species for the deposition on SiOCH and only tantalum silicide for the deposition on SiO2. We found that alpha-tantalum grows preferably on tantalum carbide and nitrogen rich intermediate layers whereas silicide at the interface promotes the growth of beta-tantalum. To verify these findings we studied two additional modifications of the interface. A lower bias power for a deposition of tantalum nitride on SiO2 was used to confirm the role of tantalum silicide and a thermal treatment of a thin tantalum layer on SiOCH was applied to confirm the role of tantalum carbide. Finally, the contact resistance in via chains on patterned wafers for four selected processes showed the same trends as the sheet resistance of the corresponding barrier films on blanket wafer experiments. KW - Tantalum KW - in situ XPS KW - Ta-phase KW - TaNx KW - Barrier KW - Interface Y1 - 2013 U6 - https://doi.org/10.1016/j.mee.2013.01.017 VL - Vol. 106 SP - 63 EP - 68 ER - TY - GEN A1 - Klein, Marten A1 - Seelig, Torsten A1 - Kurgansky, Michael V. A1 - Ghasemi, Abouzar A1 - Borcia, Ion-Dan A1 - Will, Andreas A1 - Schaller, Eberhard A1 - Egbers, Christoph A1 - Harlander, Uwe T1 - Inertial wave excitation and focusing in a liquid bounded by a frustum and a cylinder T2 - Journal of Fluid Mechanics N2 - The mechanism of localized inertial wave excitation and its efficiency is investigated for an annular cavity rotating with Ω0 . Meridional symmetry is broken by replacing the inner cylinder with a truncated cone (frustum). Waves are excited by individual longitudinal libration of the walls. The geometry is non-separable and exhibits wave focusing and wave attractors. We investigated laboratory and numerical results for the Ekman number E ≈ 10−6. inclination α = 5.71◦ and libration amplitudes ε 0.2 within the inertial wave band 0 < ω < 2Ω0 . Under the assumption that the inertial waves do not essentially affect the boundary-layer structure, we use classical boundary-layer analysis to study oscillating Ekman layers over a librating wall that is at an angle α = 0 to the axis of rotation. The Ekman layer erupts at frequency ω = f∗, where f∗ ≡ 2Ω0 sin α is the effective Coriolis parameter in a plane tangential to the wall. For the selected inclination this eruption occurs for the forcing frequency ω/Ω0 = 0.2. For the librating lids eruption occurs at ω/Ω0 = 2. The study reveals that the frequency dependence of the total kinetic energy Kω of the excited wave field is strongly connected to the square of the Ekman pumping velocity wE (ω) that, in the linear limit, becomes singular when the boundary layer erupts. This explains the frequency dependence of non-resonantly excited waves. By the localization of the forcing, the two configurations investigated, (i) frustum libration and (ii) lids together with outer cylinder in libration, can be clearly distinguished by their response spectra. Good agreement was found for the spatial structure of low-order wave attractors and periodic orbits (both characterized by a small number of reflections) in the frequency windows predicted by geometric ray tracing. For ‘resonant’ frequencies a significantly increased total bulk energy was found, while the energy in the boundary layer remained nearly constant. Inertial wave energy enters the bulk flow via corner beams, which are parallel to the characteristics of the underlying Poincaré problem. Numerical simulations revealed a mismatch between the wall-parallel mass fluxes near the corners. This leads to boundary-layer eruption and the generation of inertial waves in the corners. KW - boundary-layer structure KW - geophysical and geological flows KW - waves in rotating fluids Y1 - 2014 U6 - https://doi.org/10.1017/jfm.2014.304 SN - 1750-6859 IS - vol. 751 SP - 255 EP - 297 ER - TY - CHAP A1 - Klein, Marten A1 - Borcia, Ion-Dan A1 - Egbers, Christoph A1 - Ghasemi, Abouzar A1 - Harlander, Uwe A1 - Kurgansky, Michael V. A1 - Schaller, Eberhard A1 - Seelig, Torsten A1 - Will, Andreas T1 - Inertial Waves and Wave Excitation Mechanisms in Annular Cavities: Simulations, Experiments and Theory T2 - European Turbulence Conference ETC14, Lyon, 2013 KW - boundary-layer structure KW - geophysical and geological flows KW - waves in rotating fluids Y1 - 2013 UR - http://etc14.ens-lyon.fr/etc-14-proceedings/accepted-talks ER - TY - GEN A1 - Glawe, Christoph A1 - Schmidt, Heiko A1 - Kerstein, Alan R. A1 - Klein, Rupert T1 - XLES Part I: Introduction to Extended Large Eddy Simulation T2 - arXiv.org N2 - Direct numerical simulation (DNS), mostly used in fundamental turbulence research, is limited to low turbulent intensities due the current and future computer resources. Standard turbulence models, like RaNS (Reynolds averaged Navier-Stokes) and LES (Large Eddy Simulation), are applied to flows in engineering, but they miss small scale effects, which are frequently of importance, see e.g. the whole area of reactive flows, flows with apparent Prandtl or Schmidt number effects, or even wall bounded flows. A recent alternative to these standard approaches is the one-dimensional turbulence (ODT) model, which is limited to 1D sub-domains. In two papers we will provide a generalized filter strategy, called XLES (extended LES), including a formal theory (part I) and one special approach in the XLES family of models, called ODTLES (in part II (see Glawe et al. (2015))). ODTLES uses an ODT sub-grid model to describe all turbulent scales not represented by XLES, which leaves the larger scales to be simulated in 3D. This allows a turbulence modeling approach with a 3D resolution mainly independent of the turbulent intensity. Thus ODTLES is able to compute highly turbulent flows in domains of moderate complexity affordably and including the full range of turbulent and diffusive scales. The convergence of XLES to DNS is shown and the unconventional XLES advection approach is investigated in basic numerical tests. In part II, highly turbulent channel and duct flow results are discussed and show the future potential of XLES and ODTLES. Y1 - 2015 UR - http://arxiv.org/abs/1506.04930 ER - TY - GEN A1 - Glawe, Christoph A1 - Schmidt, Heiko A1 - Kerstein, Alan R. A1 - Klein, Rupert T1 - XLES Part II: From Extended Large Eddy Simulation to ODTLES T2 - arXiv.org N2 - In turbulence research and flow applications, turbulence models like RaNS (Reynolds averaged Navier-Stokes) models and LES (Large Eddy Simulation) are used. Both models filter the governing flow equations. Thus a scale separation approach is introduced for modeling purposes with the large scales simulated using a numerical scheme while smaller scales are assumed to be less important and might be modeled more or less easily. Unfortunately small scales are frequently of big importance, e.g. in reactive flows, wall bounded flows, or flows with significant Prandtl or Schmidt number effects. Recent alternatives to these standard models are the class of models based on the one-dimensional turbulence (ODT) idea, like ODTLES. The ability of ODT to capture highly turbulent flows (recently up to Reτ=6×105) allows ODTLES to realize 3D resolutions basically independent of the turbulent intensity. In two papers we provide a formal theory and application of an innovative modeling strategy for highly turbulent flows in domains of moderate complexity: In part I (see Glawe et al. (2015)) a new general filtering approach, called XLES (extended LES), is introduced. Contrary to LES, XLES is based on 2D filtering of the governing equations, whereby additional small scale terms are interpreted numerically. In this work a new ansatz for the ODTLES model is introduced as one special approach in the XLES family of models by incorporating the ODT model into XLES. The ODT model introduces microstructures not captured by the XLES filtered equations. To illustrate the ODTLES model capabilities, turbulent channel and duct flows up to friction Reynolds number Reτ=10000 are studied. Y1 - 2015 UR - http://arxiv.org/abs/1506.04938 ER - TY - GEN A1 - Wasmer, Kristina A1 - Köbe, Julia A1 - Andresen, Dietrich A1 - Zahn, Ralf A1 - Spitzer, Stefan G. A1 - Jehle, Joachim A1 - Brachmann, Johannes A1 - Stellbrink, Christoph A1 - Martens, Eimo A1 - Hochadel, Matthias A1 - Senges, Jochen A1 - Klein, Helmut A1 - Eckhardt, Lars T1 - Comparing outcome of patients with coronary artery disease and dilated cardiomyopathy in ICD and CRT recipients: data from the German DEVICE—registry T2 - Clinical Research in Cardiology Y1 - 2013 U6 - https://doi.org/10.1007/s00392-013-0559-0 SN - 1861-0684 SN - 1861-0692 VL - 102 IS - 7 SP - 513 EP - 521 ER - TY - GEN A1 - Boch, Steffen A1 - Allan, Eric A1 - Birkhofer, Klaus A1 - Bossdorf, Oliver A1 - Blüthgen, Nico A1 - Christ-Breulmann, Sabina A1 - Diekötter, Tim A1 - Dormann, Carsten F. A1 - Gossner, Martin M. A1 - Hallmann, Christine A1 - Hemp, Andreas A1 - Hölzel, Norbert A1 - Jung, Kirsten A1 - Klaus, Valentin H. A1 - Klein, Alexandra M. A1 - Kleinebecker, Till A1 - Lange, Markus A1 - Müller, Jörg A1 - Nacke, Heiko A1 - Prati, Daniel A1 - Renner, Swen C. A1 - Rothenwöhrer, Christoph A1 - Schall, Peter A1 - Schulze, Ernst-Detlef A1 - Socher, Stephanie A. A1 - Tscharntke, Teja A1 - Türke, Manfred A1 - Weiner, Christiane N. A1 - Weisser, Wolfgang W. A1 - Westphal, Catrin A1 - Wolters, Volkmar A1 - Wubet, Tesfaye A1 - Fischer, Markus T1 - Extensive und jährlich wechselnde Nutzungsintensität fördert den Artenreichtum im Grünland T2 - ANLIEGEN NATUR Y1 - 2016 UR - https://www.biom.uni-freiburg.de/mitarbeiter/dormann/boch2016anliegennatur.pdf SN - 1864-0729 VL - 38 IS - 1 SP - 86 EP - 95 ER - TY - GEN A1 - Glawe, Christoph A1 - Klein, Marten A1 - Schmidt, Heiko T1 - ODT augmented RaNS T2 - Book of Abstracts of the 93rd Annual Meeting of the International Association of Applied Mathematics and Mechanics KW - turbulence modeling KW - one-dimensional turbulence KW - Reynolds-averaged Navier-Stokes simulation KW - boundary layer KW - stochastic post-processing Y1 - 2023 UR - https://jahrestagung.gamm-ev.de/wp-content/uploads/2023/05/20230517_BookofAbstracts_final_red.pdf SP - 368 PB - GAMM e.V. CY - Dresden ER - TY - GEN A1 - Glawe, Christoph A1 - Klein, Marten A1 - Schmidt, Heiko T1 - Stochastic deconvolution of wall statistics in Reynolds-averaged Navier–Stokes simulations based on one-dimensional turbulence T2 - Proceedings in applied mathematics and mechanics : PAMM N2 - Reynolds-averaged Navier–Stokes simulation (RaNS) is state-of-the-art for numerical analysis of complex flows at high Reynolds number. Standalone RaNS may yield a reasonable estimate of the wall-shear stress and turbulent drag if a proper wall-function is prescribed, but detailed turbulence statistics cannot be obtained, especially at the wall. This lack in modeling is addressed here by a stochastic deconvolution strategy based on a stochastic one-dimensional turbulence (ODT) model. Here, a one-way coupling strategy is proposed in which a forcing term is computed from the balanced RaNS solution that is in turn utilized in the ODT model. The temporally developing ODT solution exhibits turbulent perturbations but relaxes toward the local RaNS solution due to resolved molecular-diffusive processes. It is demonstrated that the approach is able to recover the distribution of positive wall-shear stress fluctuations in turbulent channel flow. When formulated as post-processing tool, it is suggested that RaNS can be enhanced by ODT providing economical means for local high-fidelity numerical modeling based on a low-fidelity flow solution. KW - stochastic deconvolution KW - Reynolds-averaged Navier-Stokes simulation (RANS) KW - turbulent channel flow KW - turbulent boundary layer KW - one-dimensional turbulence Y1 - 2023 U6 - https://doi.org/10.1002/pamm.202300055 SN - 1617-7061 VL - 23 IS - 3 ER - TY - GEN A1 - Klein, Marten A1 - Medina Méndez, Juan Alí A1 - Schöps, Mark Simon A1 - Schmidt, Heiko A1 - Glawe, Christoph T1 - Towards physics-based nowcasting of the instantaneous wind velocity profile using a stochastic modeling approach T2 - STAB Jahresbericht 2024 zum 24. DGLR-Fachsymposium der STAB, 13. - 14. November 2024, Regensburg N2 - The primary objective of this contribution is to provide an overview of the regime-spanning forward modeling capabilities offered by the stochastic one-dimensional turbulence model. The focus is on the applicability of the model and its validation for neutral and stable atmospheric boundary layer flows as a prerequisite for future applications to challenging atmospheric conditions. KW - atmospheric boundary layer KW - stochastic modeling KW - one-dimensional turbulence KW - wind energy KW - wind shear and veer Y1 - 2024 UR - https://bfm.rcbe.de/files/2024/11/2024_STAB-Jahresbericht.pdf SP - 162 EP - 163 PB - Deutsche Strömungsmechanische Arbeitsgemeinschaft, STAB CY - Regensburg [et al.] ER - TY - CHAP A1 - Klein, Marten A1 - Glawe, Christoph A1 - Ehlert, Mark Simon A1 - Medina Méndez, Juan Alí A1 - Schmidt, Heiko ED - Dillmann, Andreas ED - Heller, Gerd ED - Krämer, Ewald ED - Breitsamer, Christian ED - Wagner, Claus ED - Krenkel, Lars T1 - Stochastic modeling of intermittent inflow turbulence in the atmospheric boundary layer T2 - New Results in Numerical and Experimental Fluid Mechanics XV : contributions to the 24th STAB/DGLR Symposium, Regensburg, Germany, 2024 N2 - Wind turbine predesign is challenged by the representation of site-specific wind conditions. A good deal of that challenge lies in the modeling of the inflow turbulence in the atmospheric boundary layer (ABL). A stochastic one-dimensional turbulence (ODT) model is applied to an idealized neutrally stratified ABL and evolves the instantaneous velocity profile with full-scale resolution. The model is able to reproduce the law of the wall consistently after an initial calibration with the surface drag law. Investigating turbulent time series of the horizontal velocity components it is demonstrated that the model generates physically justified intermittency features with increasing turbulence intensity. KW - Atmospheric boundary layer KW - Intermittency KW - Stochastic modeling KW - Turbulent inflow Y1 - 2026 SN - 978-3-032-11115-9 U6 - https://doi.org/10.1007/978-3-032-11115-9_63 SN - 1612-2909 SP - 684 EP - 693 PB - Springer Nature Switzerland CY - Cham ER -